A Russian SU-27 fighter jet flew dangerously close to a U.S. Air Force RC-135 reconnaissance plane, barrel-rolling on top of it over the Baltic Sea, according to the US military.

The incident Thursday occurred when a Russian jet “performed erratic and aggressive maneuvers” as it flew within 50 feet of the U.S. aircraft’s wing tip, Danny Hernandez, a spokesman for U.S. European Command, said in a response to a question from CNN.

The Russian Su-27 began the barrel roll from the left side of the U.S. RC-135 and went over the top of it to end on the right side of the aircraft, European Command said.

The RC-135 aircraft was “intercepted by a Russian SU-27 in an unsafe and unprofessional manner,” Hernandez said, adding that the U.S. plane never entered Russian territory.

“The unsafe and unprofessional actions of a single pilot have the potential to unnecessarily escalate tensions between countries,” said Hernandez, who added the United States is protesting with the Russian government.

Russia disputes reports

But Russia’s Defense Ministry said that reports on Thursday’s incident were “not consistent with reality” and that the Russian aircraft’s maneuvers had been “performed strictly in accordance with the international regulations on the use of airspace.”

Ministry spokesman Gen. Igor Konashenkov said the Su-27 had been dispatched after Russian air defense facilities spotted an unknown target over the Baltic Sea, approaching the Russian border at high speed.

It identified the jet as an American reconnaissance aircraft, and after visual contact, the U.S. plane “changed its course to the opposite direction, away from the Russian border,” he said.No incidents were recorded over the encounter, he said.